지속성 외래 복막투석 환자에서 대사성 산증이 혈청 알부민을 포함한 영양지표에 미치는 영향

Abstract

Metabolic acidosis(MA) is associated with increased proteolysis, increased osteoclast activity and blunted cardiac muscle response, but the effect of MA on various clinic al parameters in CAPD patients is not well known. To evaluate the effects of MA on serum albumin level and other nutritional parameters in CAPD patients, we studied 106 CAPD patients retrospectively who have had monthly biochemical measurement and urea kinetic studies every 6 months for more than 2 years. The patients were divided into three groups according to their mean total CO2(tCO2) level of the 2-year follow-up(Group Ⅰ; mean tCO2<22mM/L, Group Ⅱ; 22mM/L≤mean tCO2<26mM/L, and Group Ⅲ; mean tCO2≥26mM/L), and the clinical, biochemical, and urea kinetic data were compared among the three groups. 1)The mean age of the subjects was 46.9±12.2 years with a sex ratio of 1.2:1, the mean CAPD duration 28.3±21.8 months, mean body weight(Bwt) 59.0±8.9kg, %Bwt/IBW 104.1±11.5%, %LBM/Bwt 75.5±11.1% and well-nourished patients by subjective global assessment(SGA) were 65%. 2)The mean BUN, creatinine, total protein and albumin of all patients were 55.6±13.6mg/dL, 12.3±3.5mg/dL, 6.6±0.7g/dL and 4.0±0.4g/dL, respectively. In urea kinetic study, the mean NPCR, weekly Kt/ Vurea, SCCr and RRF were 0.96±0.16g/kg/day, 2.02±0.37, 63.7±18.4L/week/1.73m2, and 0.99±1.32ml/ min, respectively. 3)The mean age was significantly higher in group Ⅰ(51.0±10.8) than those of group Ⅱ(47.0±12.4) and Ⅲ(42.6±11.4)(P<0.05). %Bwt/IBW of group Ⅰ(114.4±15.8%) was also significantly higher than those of group Ⅱ(104.6±12.6%) and Ⅲ(103.5±13.7 %)(P<0.05), but there were no significant differences in sex ratio, CAPD duration, %LBM/Bwt, and SGA among the three groups. 4)The mean tCO2 in group Ⅰ, group Ⅱ, and group Ⅲ were 20.6±1.2mM/L, 23.9±1.1mM/L, and 27.3±0.8mM/L, respectively. Compared to group Ⅲ, group Ⅰ had significantly higher BUN(61.1±14.3 vs. 46.1±7.2mg/dL, P<0.05) and serum albumin(4.04±0.31 vs. 3.75±0.39g/dL, P<0.05), in spite of comparable dialysis dose and albumin loss into dialysate. 5)NPCR(1.02±0.21g/kg/day vs. 0.88±0.14g/kg/ day, P<0.05) and ultrafiltration volume(1.4±0.4 vs. 1.0±0.3, P<0.05) were significantly higher in group Ⅰ than those of group Ⅲ. But there were no significant differences in Kt/Vurea, SCCr, RRF, and 24-hour dialysate loss of protein/albumin among the three groups. 6)No differences were observed among the three groups in the changes of body weight, %Bwt/IBW, %LBM/Bwt, BUN, albumin, NPCR, and RRF from the baseline values after the 2-year follow-up. 7)There were significant inverse correlations between the mean tCO2 level and NPCR(r=-0.33, P<0.001), %Bwt/IBW(r=-0.32, P<0.001), RRF(r=-0.29, P<0.005), and serum albumin level(r=-0.24, P<0.05). But, creatinine, %LBM/Bwt, and Kt/Vurea did not show any correlation with the mean tCO2 level. 8)Using stepwise multiple regression analysis, NPCR(β=-0.3491, P<0.001), %Bwt/IBW(β=-0.046, P <0.001), and ultrafiltration volume(β=-0.0012, P< 0.005) were independent factors affecting the mean tCO2 level. In conclusion, low total CO2 level in long-term CAPD patients may reflect increased protein intake and mild to moderate degree of metabolic acidosis may not affect the nutritional status of well-dialyzed CAPD patients.